December is the only month on the birthstone calendar to feature three distinct gemstones: tanzanite, zircon, and turquoise. Each of these stones carries its own unique history, symbolism, and gemological properties, yet they are united by their beautiful blue hues and the cultural significance they’ve held across centuries. From the ancient mines of Egypt and China to the modern discoveries in Tanzania, these stones have captivated jewelers, collectors, and historians alike. In this article, we will explore the origins, physical characteristics, cultural lore, and care requirements of these three December birthstones, drawing from authoritative sources in gemology and history.
December is a month rich in symbolism and tradition, and its birthstones reflect this depth. The trio of tanzanite, zircon, and turquoise represents a convergence of rare geological phenomena, ancient cultural practices, and modern appreciation for color and form. While blue topaz is sometimes listed as an alternative December birthstone in some modern guides, the primary and most widely recognized December birthstones remain tanzanite, zircon, and turquoise. These gemstones have been cherished for their beauty and significance for thousands of years, with some of their uses tracing back to ancient civilizations.
The diversity of December's birthstones also allows for a wide range of styles and budgets in jewelry. Tanzanite, for instance, is a relatively recent discovery and is prized for its vibrant blue-violet color and rarity. Zircon, though often overshadowed by its synthetic cousin cubic zirconia, is a natural gemstone with a long history and a stunning refractive index that makes it a popular alternative to diamond. Turquoise, one of the oldest known gemstones, continues to be valued for its unique blue-green color and its use as a protective talisman in many cultures.
This article will delve into the geological formation, historical usage, gemological properties, and cultural significance of each of these stones, providing a comprehensive overview that will appeal to gemstone enthusiasts, jewelry buyers, and students of gemology.
History and Lore
Tanzanite: A Modern Discovery with Ancient Roots
Tanzanite, the youngest of December's birthstones, was discovered in 1967 in Tanzania, from which it takes its name. Found only in a small area near Mount Kilimanjaro, tanzanite is a variety of the mineral zoisite. Its striking blue-violet color and trichroism—its ability to display three different colors depending on the viewing angle—make it a unique and highly sought-after gemstone.
Despite its modern discovery, tanzanite has roots in ancient mineralogy. Zoisite itself has been known to mineralogists for centuries, but it was not until the 1960s that the blue variety was recognized as a distinct and valuable gemstone. The limited geographic source of tanzanite, combined with its vivid color, quickly made it a popular choice for jewelry, and it was officially recognized as a December birthstone soon after its discovery.
Zircon: An Ancient Gemstone with a Misunderstood Reputation
Zircon, on the other hand, is one of the oldest gemstones known to humanity. The name "zircon" is derived from the Arabic word "zarkun," which refers to a yellowish gemstone, but zircon can occur in a wide range of colors, including blue, green, red, and colorless. Blue zircon, in particular, is a popular choice for jewelry due to its high refractive index and brilliant sparkle, which is often compared to that of diamond.
Despite its natural beauty and historical significance, zircon is often confused with cubic zirconia, a synthetic diamond simulant. This confusion has led to some misunderstandings about zircon's value and quality. However, zircon has been used in jewelry for thousands of years and is known for its durability and optical properties. In fact, zircon is one of the oldest minerals on Earth, with some zircon crystals found in Australian rocks dating back over 4 billion years.
Turquoise: A Stone of Protection and Power
Turquoise is perhaps the most historically significant of the three December birthstones. It has been used in jewelry and decorative arts for thousands of years, with evidence of its use dating back to ancient Egypt, where it was believed to protect the wearer from harm and bring good fortune. The stone's name comes from the French phrase "pierre turquoise," meaning "Turkish stone," as it was originally brought to Europe through Turkey.
In many cultures, turquoise has been considered a sacred stone. Native American tribes, for example, have used turquoise in their jewelry and ceremonial objects for centuries, believing it to have healing properties and the power to ward off negative energy. In Chinese culture, turquoise has been used in carvings and inlay work for over 3,000 years, and it was highly prized by the imperial court.
Turquoise's unique blue-green color has also made it a popular choice for jewelry, particularly in regions where it is naturally found, such as the American Southwest and Central Asia. The stone is often found with matrix patterns—veins of the surrounding rock that give it a distinctive appearance.
Geological Formation and Sources
Tanzanite: A Product of Unique Geology
Tanzanite's formation is closely tied to the geology of Tanzania. It is found only in a small area near the base of Mount Kilimanjaro, in the Merelani Hills. The region is known for its complex geological history, which includes the intrusion of metamorphic rocks and the presence of high-pressure mineral assemblages. Tanzanite is a type of zoisite that has undergone a transformation due to heat and pressure, resulting in its unique blue-violet color.
The limited geographic source of tanzanite makes it one of the rarest gemstones in the world. Unlike other gemstones that can be found in multiple locations, tanzanite is exclusive to Tanzania, and its supply is expected to diminish over time due to the finite nature of the deposit. This rarity, combined with its vibrant color and trichroism, contributes to its high value in the gemstone market.
Zircon: A Mineral with a Wide Range of Origins
Zircon is a mineral that can be found in a variety of geological environments. It forms in igneous rocks during the cooling of magma and is also found in metamorphic rocks that have been subjected to high pressure and temperature. Zircon is known for its resistance to weathering and its ability to preserve geological information over billions of years, making it a valuable tool for geologists.
Blue zircon is typically formed through a process called irradiation and heat treatment. Natural zircon is often colorless or brown, but when exposed to radiation and heat, it can develop a deep blue color. This process is similar to the one used to create blue topaz and other gemstones. The blue color is stable and does not fade with time, making it a popular choice for jewelry.
Zircon is found in many parts of the world, including Australia, Thailand, Cambodia, and the United States. Each deposit produces zircons with slightly different characteristics, but all zircons share the same basic chemical composition and physical properties.
Turquoise: A Hydrated Phosphate with Ancient Roots
Turquoise is a hydrated phosphate of aluminum and copper, and it forms in the weathering zones of copper deposits. It is typically found in arid regions where the right combination of minerals and water is present. The stone is formed when acidic solutions, often containing copper from nearby ore bodies, react with aluminum and phosphorus in the surrounding rocks.
Turquoise is known for its porous structure, which makes it susceptible to changes in moisture and temperature. This porosity also allows the stone to absorb dyes and treatments, which are often used to enhance its color. However, untreated turquoise is highly valued for its natural beauty and unique patterns.
The most significant sources of turquoise today are in the American Southwest, particularly in Arizona and New Mexico. Other notable sources include Iran, China, and Egypt. Each of these regions produces turquoise with distinct colors and matrix patterns, making it a highly collectible gemstone.
Gemological Properties
Tanzanite: A Rare and Colorful Gemstone
Tanzanite is a relatively soft gemstone with a hardness of 6 to 6.5 on the Mohs scale. This makes it more susceptible to scratches and damage compared to harder gemstones like diamond or sapphire. However, tanzanite is often cut in a way that protects its facets, and it is best suited for use in jewelry that is not subject to frequent wear or abrasion.
The chemical formula for tanzanite is Ca₂Al₃(SiO₄)(OH)₂·(OH), which is the same as zoisite, but with a different crystal structure that allows for its unique coloration. Tanzanite is also known for its trichroism, a phenomenon in which the gemstone displays three different colors depending on the viewing angle. This effect is most pronounced in well-cut tanzanite, where the blue, purple, and burgundy tones can be clearly seen.
Tanzanite is typically heat-treated to enhance its color, and the treatment is stable over time. This means that the gemstone retains its vibrant blue-violet color even after exposure to light and heat. Tanzanite is also pleochroic, meaning it can display different colors in different directions, which adds to its visual appeal.
Zircon: A Gemstone with a High Refractive Index
Zircon is a hard gemstone with a hardness of 6 to 7.5 on the Mohs scale, making it more durable than tanzanite but less durable than sapphire or ruby. Its high refractive index (1.92 to 2.00) gives it a brilliant sparkle that is often compared to diamond. This makes zircon a popular choice for jewelry, particularly in rings and pendants.
Zircon is a silicate mineral with the chemical formula ZrSiO₄. It is found in a variety of colors, including blue, green, red, and colorless. Blue zircon is the most popular for jewelry, as its high refractive index and brilliant sparkle make it an attractive alternative to diamond. Zircon is also known for its double refraction, a phenomenon in which light is split into two rays as it passes through the gemstone. This can create a slightly distorted image when viewed through the stone, but it is generally not considered a flaw.
Zircon is a relatively affordable gemstone, making it a popular choice for those looking for a beautiful and durable stone without the high cost of diamonds or colored gemstones. It is also a good choice for those who want a gemstone with a unique color and a high level of brilliance.
Turquoise: A Soft and Porous Gemstone
Turquoise is a relatively soft gemstone with a hardness of 5 to 6 on the Mohs scale. Its porous structure makes it vulnerable to scratches, abrasions, and changes in moisture and temperature. This means that turquoise requires careful handling and storage to prevent damage.
The chemical formula for turquoise is CuAl₆(PO₄)₄(OH)₈·4H₂O, which gives it its characteristic blue-green color. The presence of copper gives turquoise its blue color, while the presence of iron can give it a greenish tint. The stone is often found with matrix patterns—veins of the surrounding rock that give it a distinctive appearance.
Turquoise is often treated with stabilizing agents to improve its durability and color. These treatments can include oil, wax, or resins, which are used to fill the pores of the stone and prevent it from drying out. However, untreated turquoise is highly valued for its natural beauty and unique patterns.
Turquoise is also known for its ability to change color when exposed to different conditions. It can fade in the sun or change color when it loses moisture. This makes it important to store turquoise in a cool, dry place and to avoid exposing it to direct sunlight or harsh chemicals.
Symbolism and Metaphysical Beliefs
Tanzanite: A Stone of Transformation and Spiritual Growth
Tanzanite is often associated with transformation, spiritual growth, and emotional healing. It is believed to help individuals release negative emotions and promote a sense of peace and balance. Tanzanite is also thought to enhance intuition and psychic abilities, making it a popular stone for those engaged in meditation or spiritual practices.
In many cultures, tanzanite is considered a protective stone that can shield the wearer from negative energy and promote emotional stability. It is also associated with wisdom and clarity, helping individuals to make informed decisions and navigate life's challenges with confidence.
Zircon: A Stone of Energy and Clarity
Zircon is believed to have a number of metaphysical properties, including the ability to enhance energy levels and promote mental clarity. It is often used in meditation to help focus the mind and enhance concentration. Zircon is also associated with protection and is believed to shield the wearer from negative influences and harmful energies.
In some cultures, zircon is considered a stone of good fortune and is used as a talisman to attract wealth and success. It is also believed to have healing properties, particularly for the digestive system and the liver. Zircon is also associated with love and is thought to enhance relationships and attract new connections.
Turquoise: A Stone of Protection and Positive Energy
Turquoise is one of the most well-known stones for protection and positive energy. It is believed to shield the wearer from negative influences and promote a sense of calm and well-being. Turquoise is also associated with good luck and is often used as a talisman to attract positive energy and ward off misfortune.
In Native American culture, turquoise is considered a sacred stone that is used in ceremonies and rituals. It is believed to have healing properties and is used to treat a variety of ailments. Turquoise is also associated with communication and is thought to enhance the ability to express oneself clearly and confidently.
Turquoise is also believed to have a calming effect on the mind and body, making it a popular stone for those seeking relaxation and emotional balance. It is often used in jewelry and carried as a personal talisman to promote positive energy and good fortune.
Care and Cleaning
Tanzanite: Gentle Cleaning for a Sensitive Gemstone
Tanzanite requires gentle cleaning to maintain its luster and prevent damage. It is best to use a soft cloth or a mild soap solution and a soft brush to clean the gemstone. Ultrasonic cleaners should be avoided, as they can cause damage to the stone.
It is also important to store tanzanite separately from other gemstones to prevent scratches. Tanzanite should be kept away from direct sunlight and extreme temperatures, as these can affect its color and stability. When not in use, tanzanite should be stored in a soft cloth or a jewelry box to protect it from dust and abrasion.
Zircon: A Durable Gemstone with Simple Care Requirements
Zircon is a relatively durable gemstone that can be cleaned with a soft cloth or a mild soap solution. It is best to avoid using harsh chemicals or abrasive cleaners, as these can damage the stone's surface. Zircon can also be cleaned with an ultrasonic cleaner, but it is best to check with a professional jeweler before doing so.
Zircon should be stored separately from other gemstones to prevent scratches. It is also important to avoid exposing zircon to extreme heat or cold, as this can affect its color and stability. When not in use, zircon should be stored in a jewelry box or a soft cloth to protect it from dust and abrasion.
Turquoise: A Delicate Gemstone That Requires Special Care
Turquoise is a delicate gemstone that requires careful handling and storage. It should be cleaned with a soft, slightly damp cloth, and it should never be soaked in water or exposed to harsh chemicals. These can cause the stone to fade or lose its color.
Turquoise should also be stored separately from other gemstones to prevent scratches. It is important to keep turquoise away from direct sunlight and extreme temperatures, as these can cause the stone to dry out and lose its color. When not in use, turquoise should be stored in a cool, dry place to prevent damage.
It is also important to avoid using any lotions, perfumes, or hairsprays on turquoise, as these can stain or damage the stone. If turquoise is treated with stabilizing agents, it is important to avoid exposing it to any substances that could react with these treatments.
Conclusion
December's birthstones—tanzanite, zircon, and turquoise—offer a rich tapestry of history, symbolism, and gemological significance. From the rare and vibrant tanzanite to the ancient and durable zircon, and the timeless beauty of turquoise, these gemstones have captivated people for centuries. Each stone carries its own unique story, and together they form a beautiful and meaningful trio that represents the spirit of December.
Whether you are drawn to the modern elegance of tanzanite, the brilliant sparkle of zircon, or the protective power of turquoise, there is a December birthstone for every style and preference. These gemstones not only enhance the beauty of jewelry but also serve as a connection to the past, carrying with them the traditions and beliefs of the cultures that have cherished them for generations.
As we continue to appreciate the beauty and significance of these gemstones, it is important to care for them properly to ensure that their beauty and value endure for years to come. With the right knowledge and care, December's birthstones can be cherished not only as symbols of personal significance but also as enduring works of natural art.